Polyunsaturated fatty acids, or PUFAs, are found naturally and a wide variety of different PUFAs are produced by different single cell organisms (algae, fungi, etc). One particularly important PUFA is arachidonic acid (ARA) which is one of a number of Long Chain Poly-Unsaturated Fatty Acids (LC-PUFAs). Chemically, arachidonic acid is cis-5,8,11,14 eicosatetraenoic acid (20:4) and belongs to the (n-6) family of LC-PUFAs.
Arachidonic acid is a major precursor of a wide variety of biologically active compounds, known collectively as eicosanoids, a group comprising prostaglandins, thromboxanes and leukotrienes. Arachidonic acid is also one of the components of the lipid fraction of human breast milk and is thought to be essential for optimal neurological development in infants. Arachidonic acid has a wide variety of different applications including use in infant formula, foodstuffs and animal feeds.
WO-A-97/37032 refers to the preparation of a microbial PUFA-containing oil from pasteurised biomass. However, there is no disclosure of deaeration prior to pasteurisation.
WO-A-04/001021 published on 31 Dec. 2003 describes more detailed pasteurisation conditions.
Processes involving heating biomass, or microbial cells, are known. WO-A-97/37032 describes that microbial cells can be pasteurised prior to extraction to a PUFA therefrom in the form of an oil. However, the present applicants have found that inclusion of a deaeration process can improve the quality of the oil that can be extracted from the cells. In particular, the resulting oil may oxidise less, or be less oxidised, and may have a lower peroxide value (POV) and/or anisidine value (AnV).